Stereophotogrammetric measurements of volume, area and depth characteristics of the optic cup are being performed in eyes with: (1) elevated intraocular pressure with normal optic discs and visual fields (Group I); (2) elevated intraocular pressure and early glaucomatous optic disc cupping, but normal visual fields (Group II); and (3) glaucomatous optic disc cupping with visual field loss (Group III). The mean values of optic cup volume, area, depth, and volume and area asymmetry between eyes all reflect an increase from Groups I to II to III. However, the distributions of individual values exhibit considerable overlap among the three groups, thereby limiting the differential diagnostic utility of any single measurement parameter. By establishing 95% normal confidence limits and examining a combination of all measurement parameters, 77.8% of the eyes in Group III and 64% of the eyes in Group II were detected as abnormal. In contrast, only 8.6% of the eyes in Group I fell outside of the normal confidence limits for one or more measurements. The results indicate that stereophotogrammetry may be a useful technique for detecting early glaucomatous damage prior to visual field loss. The ability of stereophotogrammetry to determine progression of glaucomatous optic disc cupping is currently being evaluated.